JP2000208275A - Electroluminescent element and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroluminescent element having a laminated type luminescent layer with effectively improved luminescent efficiency. SOLUTION: This electroluminescent element comprises a transparent conductive layer 1, binder layers 2 and 4 disposed on the back side of the transparent conductive layer 1, a light emitting particle layer 3 composed of a substantially single layer of a particle containing a light emitting particle and attached on the back side of the transparent conductive layer 1 through the binder layers 2 and 4, an insulative layer 5 disposed on the back side of the light emitting particle layer 3 and containing an insulative particle, and a back plate 6 disposed on the back side of the insulative layer 5. The light emitting particle is embedded in the binder layers 2 and 4 or the light emitting particle layer 3 is not substantially laid embedded in the insulative layer 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescence (EL) device having a light emitting layer containing light emitting particles and a binder resin, and more particularly to a "stacked light emitting layer" capable of realizing high light emission efficiency. It relates to an EL element.

[0002]

2. Description of the Related Art An EL device having a so-called "dispersed light-emitting layer" formed by dispersing light-emitting particles such as a phosphor in a binder resin such as a high dielectric constant polymer is known from the following documents. I have. For example, Japanese Patent Publication No. 59-14878
The publication discloses a transparent base material, a transparent electrode layer, an insulating layer composed of only a vinylidene fluoride-based binder resin, a light-emitting layer composed of a vinylidene fluoride-based binder resin and phosphor particles, the same insulating layer as described above, and a back surface. An EL light-emitting element in which electrodes are stacked in this order is disclosed. In addition, Tokiko Sho 6
JP-A-2-59879 discloses a polyester film, I
An EL light emitting device is disclosed in which a TO electrode, a light emitting layer comprising a cyanoethylated ethylene-vinyl alcohol copolymer (binder resin) and phosphor particles, and an aluminum foil (back electrode) are laminated in this order.

However, such a "dispersed light emitting layer"
Then, it is difficult to increase the light emission luminance. The reason is that, in the light emitting layer forming paint in which the light emitting particles are dispersed in the binder resin solution, the light emitting particles having a higher specific gravity than the binder resin are liable to settle, and in the light emitting layer formed from such a paint, This is because it is difficult to make the luminescent particles uniformly dispersed. Further, increasing the amount of the luminescent particles in the coating material in order to increase the filling rate of the luminescent particles in the luminescent layer has a limit in terms of dispersibility, and is at most 20% by volume of the coating material weight. Furthermore, it is relatively difficult to increase the coating thickness while maintaining a uniform thickness in such a dispersion-type coating, and it is necessary to increase the number of coatings to increase the thickness of the light emitting layer, resulting in poor productivity. It was also difficult to produce a large-area sheet-like EL element.

Therefore, as one means for solving the problem of the “dispersion type light emitting layer”, an E-type having a “stacked type light emitting layer” has been proposed.
L elements are known. For example, US Pat.
Nos. 9,748 and 5,045,755 include (1)
(1) a first high dielectric constant adhesive layer disposed on the transparent conductive layer of the transparent substrate; and (2) dry fluorescent particles (light emitting particles) electrostatically disposed on the first high dielectric constant adhesive layer. A substantially single-layered fluorescent particle layer (the thickness of the layer does not exceed the size of the fluorescent particle having the largest size), and (3) a high dielectric constant material disposed on the fluorescent particle layer. An EL element having a so-called “stacked light-emitting layer” is disclosed, which includes a three-layer stack of a second dielectric layer that fills a gap between adjacent fluorescent particles. The back electrode is directly provided on the surface of the second dielectric layer, that is, the second dielectric layer functions as an insulating layer. According to this method, it is easier to perform the coating operation continuously than in the case of the “dispersion type light emitting layer”, and it is also possible to produce a roll-shaped EL element.

[0005] However, in the above publications and patent specifications, a terminal (bus) for supplying electricity (voltage) from the outside to the transparent conductive layer is provided during the production process of the roll-shaped EL element. No specific means for providing such a structure so as to extend continuously in the vertical direction is disclosed. It is important to provide a terminal (bus) for supplying electricity (voltage) from the outside to the transparent conductive layer in achieving a large area of the EL element. For example, in an EL element for a small area display, a bus that is not electrically connected to the back electrode can be provided on the transparent conductive layer by effectively repeating screen printing. However,
Neither of the above publications or patent specifications disclose anything about the formation of the bus so as to extend continuously along the length direction, and no means for that.

[0006]

However, as a result of the study of the present inventors, it has been found that the conventional "stacked light emitting layer" has the following problems. That is, in the “stacked light-emitting layer”, compared to the EL element having the “dispersed light-emitting layer”, when connected to a power source of the same frequency and the same voltage, light is emitted at the same or higher luminance, but the luminous efficiency is higher. However, there is a problem that it is not so much improved or it is rather low. Here, the “luminous efficiency” is a value defined by the following equation.

[0007]

## EQU1 ## Luminous efficiency η [lm / W] = L × π × S / P (1) where P is power consumption (effective power) (unit: W), and L is luminance measured using a luminance meter. (Unit: cd / m ² ), S
Is the area of the light emitting surface (unit: m ² ), and π is the pi.

That is, low luminous efficiency means that
The luminance per unit effective power is low, which means that the power efficiency is low. Therefore, it is necessary to improve the luminous efficiency from the viewpoint of energy saving.

[0009] That is, a first object of the present invention is to provide an EL device in which luminous efficiency is effectively improved in order to solve the problems of the conventional EL device having a "stacked light emitting layer". It is in. A second object of the present invention is to provide a sheet-like E having high luminous efficiency because it is not necessary to use the dispersion paint as described above.
An object of the present invention is to provide a method for manufacturing an EL element, which can manufacture an L element with high productivity. A third object of the present invention is to provide an EL device that can be formed into a roll shape that can easily form a large-sized light-emitting display in order to solve the above-mentioned problems of the conventional technology. These and other objects of the present invention are achieved as described below.

[0010]

According to one aspect of the present invention, there is provided:
In order to achieve the first object, it comprises: a) a transparent conductive layer; b) a binder layer disposed on the back surface of the transparent conductive layer; and c) a substantially monolayer of particles comprising luminescent particles. A light-emitting particle layer adhered to the rear surface of the transparent conductive layer via a binder layer; d) an insulating layer disposed on the rear side of the light-emitting particle layer and containing insulating particles; and e) a rear surface of the insulating layer. Wherein the light emitting particles are embedded in the binder layer, or the light emitting particles are not substantially embedded in the insulating layer. An electroluminescent element characterized by the following. I will provide a.

According to another aspect of the present invention, there is provided a light-emitting device comprising: a) a transparent conductive layer; b) a binder layer disposed on the back surface of the transparent conductive layer; A luminescent particle layer consisting essentially of a single layer of particles comprising, bonded to the back of the transparent conductive layer via a binder layer,
A method for producing an electroluminescent device, comprising: d) an insulating layer disposed on the back side of the luminescent particle layer and containing insulating particles; and e) a back electrode disposed on the back side of the insulating layer. I) applying a coating for forming the first layer of the binder layer on one of the back surface of the transparent conductive layer and the surface of the insulating layer, and before the coating solidifies, the particles including the luminescent particles Are arranged in layers, the layer of the particles is partially embedded in the paint, and then the paint is solidified to form a first binder resin.
Forming a layer and a luminescent particle layer fixed to the first layer; ii) applying a coating material for forming a second layer of the binder layer on the luminescent particle layer, solidifying the coating material, and forming the luminescent material; A particle layer is embedded in a binder layer comprising a first layer and a second layer so that the luminescent particles are not exposed so that the surface thereof is not exposed. Iii) On the binder layer in which the luminescent particle layer is embedded, There is provided a manufacturing method including each step of disposing either the transparent conductive layer or the insulating layer.

According to another aspect of the present invention, in order to achieve the third object, the transparent conductive layer, the luminescent particle layer, the insulating layer, and the back electrode have a length equal to the length of the transparent conductive layer. Extending continuously along a direction, further electrically connected to the back surface of the transparent conductive layer, having a width dimension smaller than the width dimension of the transparent conductive layer, and the transparent conductive layer Further comprising at least one bus extending continuously along the length direction of the electroluminescent device of the present invention, wherein the bus is not electrically connected to the back electrode. .

One of the features of the EL device according to one embodiment of the present invention is an EL device having a luminescent particle layer formed by arranging particles containing luminescent particles substantially in a single layer. Means that it is embedded in the binder layer. Thereby, the efficiency (luminous efficiency) of the emission luminance with respect to the effective power can be improved.

The operation in this configuration is considered as follows. In the conventional stacked EL device, the gap between the phosphor particles (light-emitting particles) is filled with a filler (insulator particles or the like) having a very high dielectric constant. Capacitance increases. Therefore, the dielectric loss in the gap becomes large, and a power loss occurs due to the generation of Joule heat. As a result, the luminous efficiency is deteriorated. Usually, the dielectric constant of the insulator particles is at least 100, and may be 1,000 or more for a relatively high insulating effect such as barium titanate. On the other hand, the dielectric constant of an organic polymer or a high dielectric constant polymer that can be used as a binder resin (also referred to as a “matrix resin”) for an EL element is as follows:
It is usually less than 50, and is in the range of 5 to 30 even for a suitable high dielectric constant polymer such as a vinylidene fluoride resin or a cyano resin. In addition, "dielectric constant" in this specification is a relative dielectric constant measured by applying an AC voltage of 1 kHz unless otherwise specified. According to the configuration of the present invention, the luminescent particles are embedded in the binder layer, and the insulating particles having a very high dielectric constant do not exist in the gap between the luminescent particles adjacent to each other. The capacitance can be effectively reduced.

Another feature of an EL device according to another aspect of the present invention is that an EL device having a light-emitting particle layer formed by arranging particles containing light-emitting particles in a substantially single-layered state, That is, it is not substantially buried in the insulating layer. If the luminescent particle layer is not substantially buried in the insulating layer, a filler having a very high dielectric constant (such as an insulating particle) is provided in the gap between the phosphor particles (luminescent particles) as in the above-described embodiment. ) Is not filled. Therefore, an increase in dielectric loss in the gap and a power loss due to generation of Joule heat can be reduced as much as possible, and luminous efficiency can be improved. Such a structure can be easily achieved, for example, by embedding luminescent particles in the binder layer so that the particle surface is not exposed from the surface (back surface) of the binder layer in contact with the insulating layer, as in the above case. Can be formed.

On the other hand, according to one preferred form of the present invention, E
One feature of the L element is that the transparent conductive layer, the luminescent particle layer, the insulating layer, and the back electrode continuously extend along a length direction of the transparent conductive layer. At least one bus electrically connected to the rear surface of the transparent conductive layer, the bus having a width dimension smaller than the width dimension of the transparent conductive layer, and extending continuously along the length direction of the transparent conductive layer. Another feature is that the bus is not electrically connected to the back electrode. Thereby, it becomes easy to form a roll-shaped EL element in which it is easy to form a large light-emitting display.

If the bus is not directly connected to the light-emitting layer, it becomes easier to form a large-area roll-shaped EL element. This is because the back electrode can be arranged on substantially the entire back surface of the light emitting layer, and substantially the entire surface of the light emitting layer can emit light. For example, the vicinity of the edge of the light emitting layer can be directly connected to the bus. However, in this case, in order to dispose the back electrode and the bus separately (so as not to be electrically connected), it is necessary to provide an electrode-free portion where the bus and the back electrode are not disposed on the back surface of the light emitting layer. The light emitting surface of the light emitting layer corresponding to the electrode non-arranged portion hardly emits light, and thus it may be difficult to increase the light emitting area.

The EL device according to the present invention can be manufactured by various methods. For example, it is preferable to carry out as follows. That is, i) a coating for forming the first layer of the binder layer is applied on one of the back surface of the transparent conductive layer and the surface of the insulating layer, and contains luminescent particles before the coating solidifies. The particles are arranged in a layer, and the layer of the particles is partially embedded in the coating material.
Forming a layer and a luminescent particle layer fixed to the first layer; ii) applying a coating material for forming a second layer of the binder layer on the luminescent particle layer, solidifying the coating material, and forming the luminescent material; A particle layer is embedded in a binder layer comprising a first layer and a second layer so that the luminescent particles are not exposed so that the surface thereof is not exposed. Iii) On the binder layer in which the luminescent particle layer is embedded, A manufacturing method comprising the steps of disposing one of the transparent conductive layer and the insulating layer. As a result, an EL element with improved luminous efficiency can be manufactured with high productivity. Further, it is easy to manufacture a large-area sheet-shaped or roll-shaped EL element.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (EL Device) As shown in FIG. 1, an EL device according to one embodiment of the present invention comprises a transparent conductive layer (1) adhered on a transparent substrate (not shown), and a back surface. Electrode (6)
And a light-emitting layer sandwiched between the transparent conductive layer and the back electrode. The light emitting layer includes a first layer (2) of a binder layer that is in close contact with the transparent conductive layer, and light emitting particles that are in close contact with the first layer of the binder layer so as to be partially buried, and the remaining portion is exposed. A substantially monolayer luminescent particle layer (3)
And a second layer (4) of the binder layer adhered so as to cover the remaining portion of the luminescent particles exposed from the first layer, and an insulating layer (5) adhered to the second layer (4) of the binder layer Consists of In the example of FIG. 1, the back electrode (6) and the insulating layer (5)
And the contact surface is a substantially smooth surface.

In the example of FIG. 1, the luminescent particle layer (3) is completely embedded in the binder layer containing the binder resin and is not in contact with the insulating layer (5) containing the insulating particles. Or point contact. That is, most of the plurality of luminescent particles (such as particles having a relatively large particle size) are in point contact with the insulating layer, but the insulating particles do not enter between the luminescent particles adjacent to each other. . The surfaces of the insulating layer and the transparent conductive layer that face each other are substantially parallel to each other and are substantially smooth. Such a structure is advantageous for improving luminous efficiency. Note that the transparent conductive layer and the luminescent particles may be in contact with each other, and in that case, the emission luminance is effectively increased. Further, the interface between the insulating layer and the back electrode is generally substantially flat.

The thickness of the entire EL element is usually 50 to 3,0.
It is in the range of 00 μm. The length of the EL element is usually 1 m or more when it is in a roll shape.

Although not shown, it is preferable that the width dimension of the transparent conductive layer is larger than the width dimension of the light emitting layer, and at least one bus is formed in a portion of the transparent conductive layer where the light emitting layer is not disposed. It is. In this case, the bus is not directly connected to the light emitting layer and is not electrically connected to the back electrode. In such a form, the normal bus is disposed near both ends in the width direction of the transparent conductive layer, and along the length direction of the transparent conductive layer,
It has two stripe shapes substantially parallel to the light emitting layer with the back electrode.

The bus is not limited to the above-described shape and arrangement as long as it functions as a terminal for supplying electricity (voltage) from the outside to the transparent conductive layer when the EL element is used. For example, a bus composed of a combination of a plurality of small buses (bus portions) and extending continuously in the bar code shape along the length direction, or a plurality of circular buses continuously existing in the length direction It may be a combination of parts. That is, as long as the effects of the present invention are not impaired, even if a small bus exists discontinuously along the length direction, it may be continuous as a whole.

For example, when a desired length is cut out from a raw material of an EL element to form an EL element for a large display, the light-emitting layer must be formed so that there is no discontinuous portion on the surface of the transparent conductive layer. However, as long as the bus can function as a terminal for supplying electricity (voltage) from the outside to the transparent conductive layer, adjacent bus portions may be discontinuous with each other. The bus is formed using a conductive material and application means, which can be used for forming a back electrode, for example. As an application means, application of a paint containing a conductive material, vapor deposition, sputtering and the like are preferable. This is because a bus arranged so as to extend continuously in the length direction of the transparent substrate can be particularly easily formed during the production process of the roll-shaped EL element.

In the EL device according to a preferred embodiment of the present invention,
As described above, the luminescent particles are embedded in the binder layer,
It is characterized in that there are no insulator particles between light emitting particles adjacent to each other. Thereby, luminous efficiency can be improved. That is, the space between the luminescent particles is filled with a binder resin containing no insulating particles. in this case,
The luminescent particle layer is preferably not substantially buried in the insulating layer. "Not substantially buried in the insulating layer" means that the luminescent particle layer is not in contact with the insulating layer at all, is in point contact, or is in contact with the insulating layer. This means a state in which the particles are in contact with the insulating layer so as not to be present. In the above or the case, the surfaces of the insulating layer and the transparent conductive layer facing each other are substantially parallel and substantially smooth. Furthermore, as long as the effects of the present invention are not impaired, light emitting particles having a relatively wide particle diameter distribution may be used, and some of the light emitting particles may be embedded in the insulating layer. The particle size distribution can be defined as follows. The proportion of particles having a particle diameter of 5 times or less of the average particle diameter in the whole is usually 85% or more, preferably 90% or more, and particularly preferably 95% or more. Also, one half of the average particle diameter
The proportion of particles having the following particle diameter in the whole is usually 1% or more, preferably 2% or more, particularly preferably 3 to 25%.
Range. Particle size is SEM (scanning electron microscope)
It can be determined by observation. In the case of particles other than a true sphere, the particle diameter of one particle is
The average value of the largest dimension (for example, the major axis of the ellipse) and the smallest dimension (for example, the minor axis of the ellipse) can be regarded as the particle size of the particle.

As mentioned above, the dielectric constant of the insulating particles is usually at least 100, while the dielectric constant of the binder resin is usually less than 50. According to the above configuration, since the luminescent particles are embedded in the binder layer and are not substantially embedded in the insulating layer, the capacitance of the gap can be effectively reduced. Preferably, the binder layer is divided into two layers to form a single-layer luminescent particle layer partially embedded in the first layer and then exposed from the first layer as a means for reducing the capacity of the gap. The second layer is disposed so as to cover the luminescent particle layer, and the luminescent particles are embedded in the binder layer including the first layer and the second layer so that the surface is not exposed. In this case, both the first and second binder layers are substantially free of insulator particles. Examples of the polymer that can be used as the binder resin include THV (tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer) and the like.

When the binder layer is composed of two or more layers, the binder resin of the layer disposed on the insulating layer side preferably has a dielectric constant as small as possible and / or a dielectric tangent as small as possible. Use a small one. For example, the dielectric constant of the binder resin of the layer disposed on the insulating layer side is usually 2
It is 0 or less, preferably 15 or less, particularly preferably 1 to 10. Further, by adding glass bubbles (glass balloons or hollow spheres) to the binder layer disposed on the insulating layer side, fine bubbles can be filled to lower the dielectric constant. In this case, the diameter of the bubble is preferably smaller than that of the luminescent particles, and is usually 10 μm or less.

A substantially single-layered luminescent particle layer is formed using a paint (slurry) containing a binder resin such as a high dielectric constant polymer and luminescent particles dispersed and contained in the binder resin. May be. In this case, for example,
Using a curtain coat method or the like, the coating film is thinned without applying a shear to the paint, and a luminescent particle layer composed of a coating film having substantially the same thickness as the luminescent particles is formed. According to a coating operation in which no coating is applied to the paint, it is easy to form a light emitting layer that is continuous in the length direction. Conventional means (drying, cooling, curing, etc.) can be used for solidifying the paint (coating).

When the light emitting layer is composed of a light emitting particle layer, a binder layer and the above-mentioned insulating layer, the light emission luminance can be improved as compared with a conventional dispersion type EL device. That is, since the insulating layer and the binder layer can be formed from a paint containing no luminescent particles, the “dispersion type luminescent layer”
Unlike this, there is no problem caused by the sedimentation of the luminescent particles in the luminescent layer forming paint. Therefore, it is extremely easy to increase the filling rate of the luminescent particles in the luminescent particle layer (substantially close packing, for example, 60% by volume or more is possible), so that the emission luminance and the luminous efficiency can be easily improved. is there. An EL element having such a light-emitting particle layer is also suitable for producing a large-area roll-shaped EL element. At the same time, it is extremely easy to form a continuous light emitting layer in the length direction. The light-emitting layer having such a structure,
The luminescent particle layer can be formed by powder coating means such as spraying the luminescent particles (details will be described later).

The EL device having the light emitting particle layer as described above is preferably manufactured, for example, by the following method. First, a coating material for forming the first layer of the binder layer is applied to the back surface of the transparent conductive layer formed on the back surface of the transparent base material, and before the coating material is solidified, particles including luminescent particles are dispersed in a layer. After partially embedding the layer of particles in the paint, the paint is solidified and the first layer of binder resin and the first layer of
A light emitting particle layer fixed to the layer is formed. Next, a coating material for forming the second layer of the binder layer is applied on the light emitting particle layer, and the coating material is solidified, and the light emitting particle layer is formed in the binder layer including the first layer and the second layer. Then, the luminescent particles are embedded so that the surface is not exposed. The application of the first layer and the second layer of the binder layer can be performed by, for example, a roll coat, bar coat, knife coat, die coat, or curtain coat method. With these methods, embedding of the luminescent particle layer and smoothing of the binder layer surface can be easily performed. Subsequently, the insulating layer is disposed on the backside of the binder layer in which the luminescent particle layer is embedded. The insulating layer is preferably formed by applying a coating for the insulating layer containing a resin and insulating particles dispersed in the resin to the back surface of the binder layer and drying the coating. Finally, a back electrode is adhered to the back surface of the insulating layer to complete the EL device of the present invention.

On the other hand, a method of starting from the opposite side to the above, that is, the second layer of the binder layer, the luminescent particle layer and the binder layer are formed on the smoothed surface of the insulating layer first formed on the back electrode. A method of laminating the first layers in this order and finally laminating the transparent conductive layer (or the transparent substrate with a transparent conductive layer) can also be adopted.

According to the method as described above, it is particularly easy to form an EL device with improved luminous efficiency continuously and at high speed, that is, with good productivity. For example, usually 5m
at a coating speed of at least pm (m / min), preferably from 10 to 200 mpm, particularly preferably from 12 to 100 mpm,
Production of L elements is possible.

The ratio of the luminescent particles contained in the particles of the luminescent particle layer is preferably at least 40% by volume. 40% by volume
If it is less than the above, the effect of improving the emission luminance and the emission efficiency may be reduced. Luminance and luminous efficiency are maximized when the particles consist only of luminescent particles. Therefore, the ratio of the luminescent particles contained in the particles of the luminescent particle layer,
Particularly preferably, it is in the range of 50 to 100% by volume.

In order to prevent the luminescent particles from being substantially buried in the insulating layer, the insulating layer may be disposed at a predetermined distance (space) from the luminescent particle layer and the binder layer. In this case, the surface of the luminescent particles may be exposed from the binder layer, and the surface is exposed in an air layer (space) formed between the insulating layer and the binder layer. Such a structure can be formed by, for example, partially providing a spacer element on the backside of the binder layer in which the luminescent particles are partially embedded, and bonding the spacer element to the insulating layer. In this case, the exposed surface of the luminescent particles is exposed in an air layer (air chamber) surrounded by the binder layer, the spacer element, and the insulating layer. In such a form,
The luminescent particles are not substantially buried in the insulating layer.

(Roll EL Element) As described above, the preferred embodiment of the present invention provides an EL element that can be formed into a roll. In the roll-shaped EL element, a transparent conductive layer and a light-emitting layer (a binder layer and a light-emitting layer bonded to the transparent conductive layer via the binder layer) are disposed on a transparent base material extending continuously in the length direction. A layer comprising a particle layer and an insulating layer), a back electrode, and a bus extend continuously along the length direction of the transparent substrate. Therefore, it is extremely easy to obtain an EL element having a light-emitting layer or the like having a large area (planar dimension) continuous in the length direction. That is, a roll-shaped EL element as a raw material having a light-emitting layer continuous in the length direction was manufactured,
Store the EL element of the desired length as necessary.
It can be obtained by simply cutting out the raw material.

In the conventional production using screen printing,
The laminated portion, such as the light emitting layer and the bath, arranged on the transparent substrate can be formed only discontinuously along the length direction. Further, in the case of an original EL element manufactured using conventional screen printing, only an EL element having a size (length) that does not include the discontinuous portion can be obtained. On the other hand, when the roll-shaped EL element of the present invention is used as a raw material, application to products having various dimensions as described above becomes extremely easy.

The roll-shaped EL element is, for example, as follows:
It is preferable to manufacture by a manufacturing method including each step of 4). That is, 1) a transparent substrate having a transparent conductive layer disposed on one surface is prepared; and 2) a transparent substrate having a widthwise dimension smaller than that of the transparent conductive layer on the transparent conductive layer. Binder layer,
A light emitting layer is formed by arranging the light emitting particle layer and the insulating layer; and 3) the remaining exposed portion of the transparent conductive layer of the substrate with the light emitting layer where the light emitting layer is not formed (that is, “light emitting layer not disposed”). Portion)), a masking having a smaller width dimension than a portion where the light-emitting layer is not disposed is disposed along the length direction of the transparent substrate, and 4) a conductive material is provided on the substrate with the light-emitting layer. Applying, the back electrode made of the conductive material, the light emitting layer and the back electrode are not directly connected by the interposition of the masking or the light emitting layer non-arranged portion where the masking is removed, A bus made of the conductive material is formed.

One of the features of this method is that the light emitting layer and the back electrode and the bus are interposed by the masking or the non-light emitting layer non-arranged portion of the transparent conductive layer from which the masking is removed. In addition, the back electrode and the bus can be formed so as not to be directly connected to each other. In this method, the masking may be removed as needed, and need not be removed unless the back electrode and the bus are electrically connected to each other.
For example, the first conductive material forming the back electrode and the second conductive material forming the bus may be applied simultaneously (but in separate application devices) or in separate steps, and on masking, If the bus made of two conductive materials and the back electrode are not electrically connected,
There is no need to remove the masking. In addition, the thickness of the light emitting layer and the masking is sufficiently larger than the thickness of the bus to be formed, and the conductive material applied at the same time does not electrically connect the bus portion and the back electrode portion. In some cases, it is not necessary to remove the masking. Preferably, however, the masking is removed. This is because the back electrode and the bus, which are not electrically connected to each other, can be particularly easily formed. Further, the first and second conductive materials may be the same material or different materials. However, it is preferable that the bus and the back electrode are formed at the same time. This is because the manufacturing steps can be easily simplified and the productivity can be easily improved.

Further, by manufacturing by the following method, a large-area roll-shaped EL element having high luminous efficiency can be manufactured with high productivity. That is, I) preparing the transparent base material on which the transparent conductive layer is laminated on one surface; and II) forming the transparent base material on the transparent conductive layer so as to cover a bus forming portion forming the bath. Masking is disposed along the length direction of the base material, and a bus-forming portion on which the masking is disposed on the transparent conductive layer and a masking non-positioning portion on which the masking is not disposed are formed; III) Disposing the light emitting layer on the transparent conductive layer at the unmasked portion to form a substrate with a light emitting layer; and IV) applying a conductive material on the substrate with the light emitting layer;
Forming the back electrode made of a conductive material on the light emitting layer, applying a conductive material to a bus forming portion exposed by removing a part or all of the masking, the back electrode, The bus that is not directly connected to the light emitting layer and the back electrode is formed by the interposition of the masking or the interposition of the light emitting layer non-arranged portion from which the masking has been removed.

One of the features of this method is that masking
An object of the present invention is to dispose a light-emitting layer on a transparent conductive layer before disposing the light-emitting layer, thereby forming a bus-forming portion on which masking is disposed and a masking-non-disposed portion on which the masking is not disposed. According to this method, it is possible to easily prevent the bus forming portion on the transparent conductive layer from being damaged by scratches or the like during the bus forming stage after the light emitting layer forming process. That is, the masking in this case makes it easy to form a continuous bus in the length direction, and also functions as a protective film for the transparent conductive layer (bus forming portion).

In the case of this method, the masking is always removed, but it may be partially or completely removed. For example, in the step IV), after the first conductive material is applied on the base material with the light emitting layer, a part or all of the masking is removed to expose the bus forming part, thereby forming the exposed bus forming part. A second conductive material may be applied to the part to form the bus. Also,
After removing a part of the masking, after applying the second conductive material to the exposed bus-forming portion, the masking that is not removed and may be removed may be removed as necessary. All masking is removed. This allows
This is because the back electrode and the bus, which are not electrically connected to each other, can be particularly easily formed. Further, the first and second conductive materials may be the same material or different materials.

In a method in which the masking is also used as a protective film for the transparent conductive layer, preferably, in the step IV), after removing a part of the masking and exposing the bus forming part, the light emitting layer is removed. Applying a conductive material on a base material, the back electrode, the light emitting layer and the bus not electrically connected to the back electrode,
Form at the same time. This is because the back electrode and the bus can be formed simultaneously and particularly easily so that they are not electrically connected, and the manufacturing steps can be simplified.

It is preferable that the bath is formed by an operation of applying a conductive material (application of a coating solution, vapor deposition, sputtering, etc.). This makes it possible to particularly easily form a bus arranged so as to extend continuously in the length direction of the transparent substrate during the production process of the roll-shaped EL element. The conductive material used for forming the bus and the back electrode will be described later. Further, as a masking material, a removable adhesive tape such as a masking tape and an application tape for sealing, and a removable resin coating film used in a general coating method can be used. The masking thickness is usually 0.1 to 100 μm. Further, when the purpose is to protect the transparent conductive layer (the bus forming portion), the preferable thickness is 0.1.
３０30 μm.

Next, each component used in the present invention will be described in detail. (Transparent substrate) It is preferable to use a transparent substrate as a support for the transparent conductive layer. Conventional transparent EL is used for the transparent substrate.
Substrates such as glass and plastic films used for the element can be used. Examples of such a plastic film include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); acrylic resins such as polymethyl methacrylate and modified polymethyl methacrylate; Fluorine resin; polycarbonate resin; and films of vinyl chloride resin such as vinyl chloride copolymer.

As the transparent substrate, a single-layer film can be used, but a multilayer film can also be used. For example, when one of the multilayer films has a high transparency and contains a dye that develops a color complementary to the emission color of the light emitting layer, the whiteness of light can be increased. Such a dye can be used for rhodamine 6 when the emission color of the light-emitting layer is blue-green.
Red or pink fluorescent dyes such as G, rhodamine B and perylene dyes are preferred. A processed pigment formed by dispersing these dyes in a resin can also be used. The front and back surfaces of the transparent substrate are generally flat, but the surface that is not in contact with the transparent conductive layer may have a prism-shaped protrusion as long as the effects of the present invention are not impaired.

The light transmittance of the transparent substrate is usually at least 60%, preferably at least 70%, particularly preferably at least 80%. Here, the “light transmittance” in this specification refers to an ultraviolet / visible spectrophotometer “model number: U bes” manufactured by JASCO Corporation.
tV-560 "means the light transmittance measured using 550 nm light. The thickness of the transparent substrate is usually 10 to 1,0 when forming a roll-shaped EL element.
00 μm. Further, as long as the effects of the present invention are not impaired, additives such as an ultraviolet absorber, a moisture absorbent, a coloring agent, a fluorescent substance, and a phosphorescent substance may be contained in the transparent substrate.

(Transparent Conductive Layer) The transparent conductive layer is disposed so as to be in close contact with the back surface of the transparent substrate. As the transparent conductive layer, a transparent electrode such as an ITO (Indium Tin Oxide) film used for a dispersion type EL element can be used. The thickness of the transparent conductive layer is usually 0.01 to 1,000 μm,
The surface resistance is usually 500 Ω / □ or less, preferably 1 to 3
00Ω / □. The light transmittance is usually 70% or more,
It is preferably at least 80%.

The ITO film is formed by ordinary film forming means such as vapor deposition, sputtering, and application of a paste. IT
The O film is usually provided directly on the transparent substrate, but after providing a primer layer on the transparent substrate, an ITO film may be formed on the primer layer. The thickness of the primer layer is usually 0.1 to 100 μm. Further, instead of the primer layer, the surface of the transparent substrate may be subjected to an easy adhesion treatment such as a corona treatment. Alternatively, after providing an ITO film on the light emitting layer, a transparent substrate can be laminated on the ITO film. Further, the ITO film provided on the release treatment surface of the temporary base material can be transferred to the back surface of the transparent base material via a transparent adhesive. As such a temporary base material, a release paper, a release film, a low molecular weight polyethylene film or the like can be used.

(Back Electrode) The back electrode is disposed on the back side of the light emitting layer (on the insulating layer side of the light emitting layer). In the form of FIG.
It is arranged so as to be in direct contact with the light emitting layer. Further, an adhesive layer may be provided between the light emitting layer and the light emitting layer for the purpose of increasing the adhesive strength to the back electrode. As the resin of the adhesive layer, for example, the same resin as a binder resin described later is used. In addition, the adhesive layer may contain insulating inorganic particles.

As the back electrode, a metal film such as aluminum, gold, silver, copper, nickel and chromium used for the dispersion type EL device; a transparent conductive film such as an ITO film; and a conductive film such as a conductive carbon film. Can be used. Such a conductive film is
It is preferable to provide by applying means such as application of a paint containing a conductive material (bar coating, spray coating, curtain coating, etc.), vapor deposition, sputtering and the like. The metal film is, for example, a deposited film, a sputtered film,
Or a metal foil or the like. Further, as the back electrode, an electrode film obtained by providing the above conductive film on a support such as a polymer film can also be used. The thickness of the back electrode is usually 5 nm to 1 mm. When the back electrode is also made of a transparent conductive film and the insulating layer is transparent, it is possible to emit light on both the front and back surfaces of the EL element.

(Binder Layer) The binder layer is preferably disposed so as to be in close contact with the back surface of the transparent conductive layer. Thereby, the luminous efficiency of the light emitting layer can be easily increased. The binder layer is a transparent layer containing a binder resin.
The thickness of the first layer and the second layer of the binder layer is usually 0.5 to 1,000 μm, respectively, and the light transmittance is usually 70% or more, preferably 80% or more. The thickness of the entire binder layer (including the case where the binder layer is composed of a single layer or two or more layers) is usually 1.0 to 2,000 μm.
m, and the light transmittance is usually 70% or more, preferably 80% or more.

Binder resins include, for example, high dielectric constant polymers, relatively low dielectric constants (eg, less than 5).
Polymers and the like can be used. The high dielectric constant polymer usually has a dielectric constant of about 5 or more, preferably 7 to 25, particularly preferably 8 to
18 range of polymers. If the dielectric constant is too low, the light emission luminance may not be increased, and if it is too high, the light emission efficiency may not be increased. Examples of the high dielectric constant polymer include, for example, vinylidene fluoride resin (T
HV, etc.), a cyano-based resin, a polyvinylidene chloride-based resin, etc. can be used alone or in combination of two or more. Vinylidene fluoride resin, for example,
It is obtained by copolymerization of a mixture of a vinylidene fluoride monomer and at least one other fluorine-based monomer. Other fluorine-based monomers, for example, tetrafluoroethylene,
Ethylene trifluoride, propylene hexafluoride and the like.
Cyano resin, for example, cyanoethyl cellulose,
Cyanoethylated ethylene-vinyl alcohol copolymer,
Cyanoethyl pullulan, cyanoethyl polyvinyl alcohol and the like.

Usually, the binder layer is composed of only the binder resin, but within the range not impairing the effects of the present invention.
Other resins, fillers, air bubbles, hollow or solid glass microspheres, surfactants, UV absorbers, antioxidants, fungicides,
Additives such as a rust inhibitor, a moisture absorbent, a coloring agent, and a phosphorescent substance may be contained. For example, when the luminescent color of the luminescent particle layer is bluish green, a red or pink fluorescent dye such as rhodamine 6G, rhodamine B, or a perylene dye may be contained. Further, the other resin may have curability or tackiness as long as the transparency is not impaired. In order to lower the dielectric constant of the binder layer disposed on the insulating layer side, bubbles and hollow glass microspheres can be filled.

(Insulating Layer) The insulating layer of the light emitting layer is indispensable for effectively preventing dielectric breakdown of the light emitting layer. Therefore, the insulating material contained in the insulating layer is, for example, a dispersion type E
The dielectric constant of the insulating inorganic particles used for the L element is 10
Zero or more substances. The insulating layer is usually
It is a coating layer formed from a paint formed by dispersing insulator particles. As the resin for the insulating layer, a high dielectric constant polymer used for the binder layer is preferable. Examples of the insulator particles are inorganic particles such as titanium dioxide and barium titanate. The insulating layer can be provided, for example, by coating on a back electrode or a binder layer in which a luminescent particle layer is embedded.

When the insulating layer is a coating layer containing insulating particles and a high dielectric constant polymer, the mixing ratio of the insulating particles is 1 to 400 parts by weight with respect to 100 parts by weight of the high dielectric constant polymer. Parts by weight, preferably 10 to 350 parts by weight,
Particularly preferably, it is in the range of 20 to 300 parts by weight. If the amount of the insulating particles is too small, the insulating effect is reduced, and dielectric breakdown may occur when a relatively high voltage is applied. Conversely, if the amount is too large, application of the paint may be difficult. The thickness of the insulating layer is usually 2 to 1,000 μm. In addition, in the insulating layer, a filler, a surfactant, an antioxidant, an antifungal agent, a rust inhibitor, a moisture absorbent, a coloring agent, a phosphorescent substance, a curable resin, an adhesive, etc., as long as the insulating property is not impaired. Additives can also be included.

(Light Emitting Particle Layer) The light emitting particles of the light emitting particle layer are as follows:
The particles emit light when placed in an AC electric field. For example, phosphor particles used in a light emitting layer of a dispersion type EL element can be used. The phosphor is, for example, ZnS, C
A single fluorescent compound such as dZnS, ZnSSe, CdZnSe, or a fluorescent compound such as Cu, I, Cl, Al, M
It is composed of a complex to which auxiliary components such as n, NdF ₃ , Ag, and B are added. The average particle diameter of the phosphor particles is usually 5 to 100.
μm. Alternatively, a phosphor having a coating film of glass, ceramics, or the like on the surface of the particle-shaped phosphor may be used. The thickness of the luminescent particle layer is usually from 5 to 500 μm.
In addition, it is preferable that the luminescent particle layer is composed of a plurality of particles arranged substantially in a single layer, because the thickness of the EL element can be easily reduced.

Further, the luminescent particle layer may contain two or more kinds of luminescent particles. For example, a light-emitting layer with high whiteness can be formed by mixing at least two kinds of light-emitting particles that emit light of colors such as blue, blue-green, green, and orange and have spectra that are independent of each other. The luminescent particle layer may contain one or more kinds of particles other than the luminescent particles (particles made of glass, coloring material, phosphor, polymer, inorganic oxide, and the like). For example, a light-emitting particle that emits blue-green light and a pink colorant (particles containing rhodamine 6G, rhodamine B, perylene dye, etc.) having a complementary color to the light are mixed to obtain a high whiteness. A light-emitting layer can be formed.

(Formation of Light Emitting Layer) The laminated structure of the light emitting layer composed of the binder layer, the light emitting particle layer and the insulating layer is formed, for example, as follows. First, a luminescent particle layer is formed on a transparent conductive layer by a usual powder coating means. For example, a binder layer is applied to the back surface of the transparent conductive layer, and in a state where the binder layer has fluidity, the particles including the luminescent particles are applied to the binder layer by an application method such as an electrostatic suction method, a spray method, or a gravity spray method. After the particles are completely buried in the binder layer, the fluidity of the binder layer is lost, and the binder layer and the particle layer are adhered to each other. When the binder layer is composed of two layers, a light-emitting particle layer in which light-emitting particles are partially buried is formed in the first layer, and then the fluidity of the first layer is lost. The layers are brought into close contact with each other, and then the exposed surface of the luminescent particles is completely covered with the second layer to form a luminescent particle layer embedded in the binder layer.

In order to make the binder layer have fluidity, a method of keeping a coating layer formed from a coating material for a binder layer containing a solvent in an undried state, a temperature higher than the softening point or melting point of the resin for the binder layer or more. It is preferable to keep the binder layer in the coating layer, or to include a radiation-curable monomer or oligomer in the coating material for the binder layer. According to these methods, a solidifying operation (drying, cooling or hardening) for losing the fluidity of the binder layer is easy.

An insulating layer is laminated on the binder layer formed as described above to form a laminated structure in which these layers are in close contact with each other. The insulating layer is preferably laminated by applying a paint containing the material forming the layer and solidifying the same, or by crimping a film made of the material forming the layer. According to these methods, a highly durable light emitting layer in which the binder layer, the light emitting particle layer, and the insulating layer are in close contact with each other can be reliably formed.

In the luminescent particle layer formed as described above, the binder resin usually enters the gaps between the particles. In this case, the filling rate of the particles is usually 20% by volume or more,
It is preferably at least 30% by volume, particularly preferably at least 40% by volume. This is because a decrease in the filling rate may cause a decrease in light emission luminance and light emission efficiency. Here, the “particle filling rate” refers to the total volume of particles relative to the total volume of the assumed layer, assuming a layer composed of all the particles of the luminescent particle layer and a material other than the particles existing between the particles. Is defined as a percentage of Furthermore, as long as the effects of the present invention are not impaired, the insulating layer may be a laminate of two or more layers.

(Method for Manufacturing EL Element) Here, one preferred embodiment of a method for manufacturing the entire EL element according to the present invention will be described. First, prepare a transparent substrate having a transparent conductive layer laminated on the back surface, and on the back surface of the transparent conductive layer, as described above,
A binder layer containing the luminescent particle layer embedded therein is brought into close contact.
At this time, the rear surface of the transparent conductive layer is usually made a substantially smooth surface. When the binder layer is composed of two or more layers, the particles are usually 1 to 99%, preferably 10 to 90%, of the vertical length of the particles (for example, “diameter” for substantially spherical particles). Particularly preferably, 20 to 80% of the portion is buried in one of the binder layers. If the burial ratio is less than 1%, the particle layer may be damaged at the stage of forming the other layer. Conversely, if the burying ratio exceeds 99%, the particle layer may not be formed into a uniform single layer. There is. When a bath is provided, the binder layer is formed so as to have a widthwise dimension smaller than that of the transparent conductive layer.

The coating thickness of the binder layer is selected so that the dry thickness falls within the above range. The solid content concentration of the coating material of the binder layer is usually in the range of 5 to 80% by weight even when the binder layer is a single layer or when the binder layer is composed of two or more layers. The solvent used for the paint is selected from ordinary organic solvents so that the binder resin can be uniformly dissolved.
Mixing and kneading apparatuses such as a homomixer, a sand mill, and a planetary mixer can be used for preparing the coating. A coating device such as a bar coater, a roll coater, a knife coater, and a die coater can be used for the coating operation. The drying conditions depend on the type of solvent and the solid content of the paint.
The temperature is appropriately selected within a range from normal temperature (about 25 ° C.) to 150 ° C. for 5 seconds to 1 hour.

The application of the particles containing the luminescent particles is carried out by the above-mentioned method, usually within 3 minutes after the application of the paint for the binder layer. Thereby, embedding of particles can be facilitated. The degree of drying of the paint of the binder layer at this time,
Although it depends on the wettability between the particles and the binder layer (that is, how easily the dispersed particles are buried in the binder layer before drying), it is usually 10 to 95% by weight in terms of solid content, preferably 10 to 95% by weight. It is in the range of 20-90% by weight. In addition, if a paint having such a solid content is used, it is easy to smooth the back surface (the surface on which the insulating layer is formed) of the binder layer in which the luminescent particle layer is embedded. In this case, the back surface of the binder layer is substantially parallel to the back surface of the transparent conductive layer.

After forming the binder layer in which the luminescent particle layer is embedded as described above, subsequently, a paint for forming an insulating layer is applied, and the paint is dried. The coating thickness of the insulating layer is
The dry thickness is selected to be in the above range. The solid content concentration of the paint is usually in the range of 5 to 70% by weight. By using a paint having such a solid concentration, it is easy to smooth the surface of the insulating layer (the surface facing the transparent conductive layer). The solvent used for the paint is selected from ordinary organic solvents so that the insulating particles can be uniformly dissolved or dispersed. For the preparation and application of the paint, the same apparatus and equipment as used for forming the binder layer can be used. The drying conditions depend on the type of solvent and the solid content of the paint.
The temperature is appropriately selected within a range from normal temperature (about 25 ° C.) to 150 ° C. for 5 seconds to 1 hour.

Finally, a back electrode layer is formed on the insulating layer. When a roll-shaped EL element is formed, a bus is formed in a portion of the transparent conductive layer where the light emitting layer is not provided. At this time, as described above, the bus is formed by using a means such as masking so as not to be electrically connected to the light emitting layer and the back electrode. The method described above can be used for forming the back electrode. However, a vacuum thin film forming method such as vapor deposition and sputtering is suitable for providing the insulating layer after drying efficiently and with good adhesion. The same method as the above-described method for forming the back electrode can be used for forming the bus.

The back electrode is usually the light emitting layer (ie,
It is continuously arranged on the entire back surface (of the insulating layer). However, it can be partially provided according to the purpose. For example, a continuous image (pattern,
(Characters, symbols, etc.). Thereby, the EL element can emit light so as to represent an image. For the same purpose, the light emitting layer may be repeatedly formed in the longitudinal direction so as to represent a continuous image.

In the above-described manufacturing method, since each step is substantially the same as that of a normal roll-shaped article, the manufacturing process of the normal roll-shaped article is used, and a large luminance and a high luminous efficiency are obtained. A roll-shaped EL element having a large area can be manufactured with high productivity. Further, since it is not necessary to use a luminescent particle-dispersed paint as in the related art, all problems caused by the dispersed paint can be solved.

As another method similar to the above method, first, an insulating layer paint is applied on a support including a back electrode, dried to form an insulating layer, and then a luminescent particle layer is embedded thereon. To form a binder layer containing, followed by dry laminating a transparent substrate with a transparent conductive layer, and finally, if necessary,
A manufacturing method including a series of steps of laminating a bus on a portion of the transparent conductive layer where the light emitting layer is not disposed is also suitable. In this case, the width dimension of the back electrode is smaller than the width dimension of the transparent conductive layer, and the bus is not directly connected to the back electrode and the light emitting layer.

(Method of Using EL Element) The EL element of the present invention can be used for internally illuminated signboards, road signs, decorative displays, and the like.
Can be used as a light source for large displays. For example,
Images such as characters and designs are provided on the surface of the light-transmitting sheet, and the light-transmitting sheet is arranged and used so that the back surface of the sheet faces the light emitting surface of the EL element. For the light-transmitting sheet, for example, the same material as the above-mentioned transparent substrate can be used, and its light transmittance is usually 20% or more. At this time, the back of the seat and E
It is preferable that the light emitting surface of the L element is in close contact with the light emitting surface. In order to make them adhere to each other, a light-transmitting adhesive is used. Such an adhesive is, for example, an acrylic pressure-sensitive adhesive, an acrylic heat-sensitive adhesive, or the like.

Further, a light-transmitting sheet is used as the above-mentioned transparent substrate, a transparent conductive layer is directly provided on the back surface of the light-transmitting sheet, and a light-emitting layer is laminated on the conductive layer to constitute a display device with a built-in EL. You can also. Further, a prism type retroreflective sheet can be used as a light-transmitting sheet (or a transparent substrate). Combination with a retroreflective sheet
The retroreflective property and the self-luminous performance can be provided to the EL built-in display body.

Light emission of the EL element is usually performed by connecting a power supply to a bus on the transparent conductive layer and a terminal provided on the back electrode layer, and applying a voltage to the element. For example, a battery such as a dry battery, a storage battery, or a solar battery is used, or an alternating current supplied from a power transmission line is converted through an inverter (a device that changes the magnitude of a voltage or frequency or converts between AC and DC). To the EL element. AC frequency is usually 50 ~ 1,0
The range is 00 Hz. The applied voltage is usually 3 to 2
It is in the range of 00V. Since the EL device of the present invention has a high luminous efficiency, the voltage (for example, 10
0 V or less) and sufficient brightness (for example, 50 cd / m
² or more). When the EL element is used outdoors, it is preferable to use the EL element by covering it with a water capture film made of a polyamide resin or the like or a moisture-proof film made of a polytetrafluoroethylene film or the like.

In the EL device of the present invention, a coloring material such as a dye or a pigment is contained in a component located in the optical path of light from the luminescent particles such as a transparent base material and a binder layer for the purpose of adjusting the luminescent color. You can also. In addition, a wavelength conversion layer containing a fluorescent dye or a fluorescent pigment, which is excited by light from the luminescent particles and emits light of a different wavelength from the light from the luminescent particles, can be arranged in the optical path of the light from the luminescent particles. . As the wavelength conversion layer, a component located in the above optical path containing a fluorescent dye or a fluorescent pigment can also be used.

[0074]

Example 1 Formation of EL Element In this example, a roll-shaped EL element having a light emitting layer having the structure shown in FIG. 1 was formed. As a roll-shaped transparent substrate, a PET film with ITO having a width of 320 mm and a length of 60 m manufactured by Oike Industry Co., Ltd. “Product number: TCF / KPC3”
00-75A (thickness: 75 μm, light transmittance: 81%) ”. On one surface of this film, a transparent conductive layer made of ITO (indium-tin-oxide) was laminated by a sputtering method. The thickness of the ITO layer is 50
nm, and the surface resistance was 250 Ω / □.

A coating for forming the first layer of the binder layer was applied to the ITO surface of the transparent substrate at a rate of 5 g / m 2 using a bar coater.
^With a coating weight of ² , coating was performed so as to form a continuous layer along the length direction of the substrate. This coating material has a high dielectric constant polymer (tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer “product number: THV200P” manufactured by 3M Co., Ltd.) as a binder resin; a dielectric constant of 10 (1 k
Hz) and a light transmittance of 96%) as a 15% by weight solution (solvent: ethyl acetate / methyl isobutyl ketone = 1: 1).

Immediately after the application of the paint, the luminescent particles (phosphor particles manufactured by Durel, product number: 6) were sprayed with a spray coater (product number: K-III spray) manufactured by Nikka Co., Ltd.
15A, average particle diameter = 15 to 25 μm, the ratio of particles having a particle diameter in the range of 5 to 35 μm to the total is about 100.
% Of the particles having a particle diameter in the range of 5 to 10 μm is about 3%. The particle diameter was determined by SEM observation. (N is 125)) at 65 ° C for about 1
And dried at 125 ° C. for about 3 minutes. Thereby, a substantially single-layer phosphor particle layer (light-emitting particle layer)
Was bonded to the back surface of the transparent conductive layer via the binder layer to obtain a laminate. The phosphor particles were embedded so that about 30% of the particle diameter was embedded in the binder layer. The coating amount of the phosphor particles was about 65 g / m ² , and the thickness of the luminescent particle layer was 33 μm. Further, the above-mentioned laminate was subjected to a coating operation such that exposed portions (non-coated portions) having a width of about 30 mm were formed at both ends in the width direction of the ITO surface.

Next, a coating for forming the second layer of the binder layer was applied and dried in the same manner as the first layer so as to cover the luminescent particle layer. As this coating material, the same solution as that for forming the first layer of the binder layer was used.

Subsequently, a coating for forming an insulating layer was applied on the back surface of the second layer of the binder layer, and the coating was dried to form an insulating layer. The composition of the paint for forming the insulating layer is as described in the above T.
HV200P: barium titanate: ethyl acetate: methyl isobutyl ketone = 11: 26: 31: 31 (weight ratio)
It was applied with a bar coater so that the coating weight after drying was 27 g / m ² , and dried under the same conditions as in the case of the binder layer described above. The barium titanate was “Product number: HPBT-1” manufactured by Fuji Titanium Co., Ltd. The thickness of the entire light-emitting layer after drying was 40 μm.

In the light emitting layer thus obtained, the light emitting particle layer was completely embedded in the binder layer, but was not substantially embedded in the insulating layer. The surfaces of the insulating layer and the transparent conductive layer facing each other were substantially parallel to each other and were substantially smooth. By the above operation, a transparent substrate with a light emitting layer provided with a light emitting layer extending continuously in the length direction was obtained.

On the other hand, the sealing application tape “3M” was formed such that exposed portions having a width of about 5 mm were formed at both ends in the width direction of the ITO surface of the transparent base material having the light emitting layer.
(Product number) 2479H (18 mm width) "was applied and masked along the length direction of the transparent base material.
Finally, after vacuum-depositing aluminum on the surface to be coated of the transparent substrate with a light-emitting layer (the surface comprising the light-emitting layer, the masking, and the exposed ITO surface), the masking is removed, and both are made of an aluminum-deposited film. It was formed simultaneously with the back electrode and the bus (two at both ends). Thus, a roll-shaped EL element of this example was obtained. The vacuum deposition of aluminum is performed at a degree of vacuum (pressure in the chamber) of 3.0 × 10 ⁻⁴ or more.
The test was performed under the conditions of 5.0 × 10 ⁻⁴ Torr and a line speed of 90 m / min.

A non-deposited portion was formed between the back electrode and the two buses, and these buses were not electrically connected to both the light emitting layer and the back electrode. Further, the bus was a striped bus extending continuously in the length direction and having no discontinuous portions. For confirmation, the cross section of the EL element of this example was observed with a scanning electron microscope. As a result, a binder resin was filled between phosphor particles adjacent to each other, and no insulator particles were observed.

Light emission of EL element From the roll-shaped EL element (raw material) thus obtained,
Cut out the rectangular EL element and set 100 between the back electrode and the bus.
When an AC voltage of 400 V was applied to the EL element to emit light, uniform light emission was obtained over the entire light emitting surface. The plane size of the light emitting surface of the rectangular EL element is
It was 100 mm (vertical) x 100 mm (horizontal). EL
In order to make the device emit light, a power supply device (product number: PCR500 manufactured by Kikusui Electronics Co., Ltd.) is provided between the ITO surface and the back electrode.
L "), and a sine wave of 100 V, 400 Hz was applied. Power meter (manufactured by Yokogawa Electric Corporation, "Model: WT
−110E ”) and a luminance meter (manufactured by Topcon Corporation,“ product number: BM-8 ”), and the effective power P [W] and the luminance L [cd / m ² ] during light emission are measured in a dark room. The light emission luminance and the light emission efficiency η [Im / W] were calculated using the above-mentioned equation (1). As a result, the effective power was 0.61 W, the emission luminance was 83 cd / m ² , and the emission efficiency was 4.3 lm (lumen) / W.

Comparative Example 1 The formation of the second layer of the binder layer after the emission of the luminescent particles was omitted.
The EL of this example was prepared in the same manner as in Example 1 except that the above-mentioned paint for forming an insulating layer was applied instead of the paint for forming a second layer.
An element was formed. Observation of the cross section of the EL element of this example with a scanning electron microscope revealed that a binder resin and insulator particles were filled between the phosphor particles. For the EL element of this example, the measured effective power, emission luminance, and emission efficiency were 1.3 W, respectively, as in Example 1.
103 cd / m ² and 2.5 lumens / W.
The luminous efficiency was reduced by about 40% as compared with Example 1.

Example 2 Example 1 was repeated except that the high dielectric constant polymer of the binder layer and the insulating layer was changed to a cyanoresin “product number: CR-M (dielectric constant = 18)” manufactured by Shin-Etsu Chemical Co., Ltd. Similarly, an EL element of this example was formed. For confirmation, E in this example was used.
When the cross section of the L element was observed with a scanning electron microscope,
The binder resin was filled between the phosphor particles adjacent to each other, and no insulator particles were observed. E in this example
For the L element, the measured effective power, emission luminance, and emission efficiency were 0.3
6 W, 75 cd / m ² and 6.5 lumen / W.

Comparative Example 2 An EL device of this example was formed in the same manner as in Example 1 except that the light emitting layer was changed to “dispersion type”. The dispersion type light emitting layer was formed using a paint containing 45 parts by weight of phosphor particles with respect to 100 parts by weight of the solution for forming the binder layer.
With respect to the EL element of this example, the measured effective power, emission luminance, and emission efficiency were 1.7 W, 65 cd / m ^2, and 1.2 lumens / m, respectively, as in Example 1.
W. The luminous efficiency was reduced by about 70% as compared with Example 1.

Comparative Example 3 An EL element of this example was prepared in the same manner as in Comparative Example 1 except that the high dielectric constant polymer of the binder layer and the insulating layer was changed to the cyanoresin “product number: CR-M” used in Example 2. Was formed. Observation of the cross section of the EL element of this example with a scanning electron microscope revealed that a binder resin and insulator particles were filled between the phosphor particles. About the EL element of this example,
In the same manner as in Example 1, the measured effective power, emission luminance and emission efficiency were 0.74 W and 95 cd /
m ² and 4.0 lumens / W. The luminous efficiency was reduced by about 40% as compared with Example 2.

[0087]

According to the present invention, the luminous efficiency is improved.
A stacked EL element can be provided. According to the present invention,
There is no need to use a dispersion paint for the light emitting layer, high light emission brightness,
A large-area sheet-like EL element having high luminous efficiency can be manufactured with high productivity. According to the manufacturing method of the present invention, for example, a width of 25 to 200 cm and a length of 100 to 20,000
Starting from a roll of a 0 m transparent substrate, a transparent conductive layer, a binder layer, a luminescent particle layer, an insulating layer, and a back electrode are successively laminated to mass-produce a large-area sheet-like EL element. It is possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a preferred embodiment of an electroluminescent device according to the present invention.

[Explanation of symbols]

 1: transparent conductive layer 2: first layer of binder layer 3: light emitting particle layer 4: second layer of binder layer 5: insulating layer 6: back electrode

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yoshinori Araki 5500, Wakagi, Higashi-ne, Yamagata Prefecture Inside Yamagata 3M Co., Ltd. F term (reference) 3K007 AB02 AB03 AB18 BA01 BA07 CA06 CB01 DA05 EA02 EB00 FA01

Claims (4)

[Claims] 1. a) a transparent conductive layer; b) a binder layer disposed on the back of the transparent conductive layer; and c) a substantially single layer of particles comprising luminescent particles, with the binder layer interposed therebetween. A luminescent particle layer adhered to the back surface of the transparent conductive layer; d) an insulating layer disposed on the back side of the luminescent particle layer and containing insulating particles; and e) a back electrode disposed on the back side of the insulating layer. An electroluminescent device comprising: the electroluminescent device, wherein the luminescent particles are embedded in the binder layer. 2. a) a transparent conductive layer; b) a binder layer disposed on the backside of the transparent conductive layer; and c) a substantially single layer of particles comprising luminescent particles, with the binder layer interposed therebetween. A luminescent particle layer adhered to the back surface of the transparent conductive layer; d) an insulating layer disposed on the back side of the luminescent particle layer and containing insulating particles; and e) a back electrode disposed on the back side of the insulating layer. Wherein the luminescent particles are not substantially embedded in the insulating layer. 3. The transparent conductive layer, the luminescent particle layer, the insulating layer, and the back electrode extend continuously along a length direction of the transparent conductive layer, and further include a back surface of the transparent conductive layer. At least one bus electrically connected to the transparent conductive layer, having a width dimension smaller than the width dimension of the transparent conductive layer, and extending continuously along the length direction of the transparent conductive layer. 3. The electroluminescent device according to claim 1, further comprising a bus, wherein said bus is not electrically connected to said back electrode. 4. It comprises a) a transparent conductive layer, b) a binder layer disposed on the back side of the transparent conductive layer, and c) a substantially single layer of particles comprising luminescent particles, with the binder layer interposed therebetween. A luminescent particle layer adhered to the back of the transparent conductive layer; d) an insulating layer disposed on the back side of the luminescent particle layer and containing insulating particles; and e) a back electrode disposed on the back side of the insulating layer. ,
And i) applying a paint for forming a first layer of a binder layer on one of the back surface of the transparent conductive layer and the surface of the insulating layer, Before the paint is solidified, the particles including the luminescent particles are arranged in a layer, and the layer of the particles is partially embedded in the paint, and then the paint is solidified to form a first binder resin.
Forming a layer and a luminescent particle layer fixed to the first layer; ii) applying a coating material for forming a second layer of the binder layer on the luminescent particle layer, solidifying the coating material, A particle layer is embedded in a binder layer comprising a first layer and a second layer so that the luminescent particles are not exposed so that the surface thereof is not exposed. Iii) On the binder layer having the luminescent particle layer embedded therein A manufacturing method, comprising the steps of i) to iii), wherein one of the transparent conductive layer and the insulating layer is disposed.